顶塔岩

在地質學中，顶塔岩（英語：）是指從大型火成岩侵入體（如岩磐）頂部向上突出的塔型部分。它也可能是一個小型火成岩侵入體，但在深處與較大的火成岩侵入體相連[1]。顶塔岩的岩漿房可能在玄武質岩漿體上方經過分化形成的中性岩或長英質岩漿，到達地表后，產生中性岩或長英質熔岩[2]。

顶塔岩的底部一般連接到花崗岩[3][4]，故多爲長英質。其侵入到圍岩時，帶入大量岩漿熱液。造成圍岩接觸變質，其中交代作用。可使岩石的裂隙中受到熱液滲入，溶解於熱液中的離子就可能與岩石中的礦物結晶反應。造成陽離子的取代[5]。形成多種經濟礦床[6][7][8]。

參考文獻
  1. Hawley, C. C. (1969). "Geology and Beryllium Deposits of the Lake George (or Badger Flats) Beryllium Area, Park and Jefferson Counties, Colorado". United States Department of the Interior. United States Government Publishing Office: A23.
  2. Charland, Anne (1994). Stratigraphy, Geochemistry and Petrogenesis of the Itcha Range Volcanic Complex, Central British Columbia (PhD). McGill University. p. 221.
  3. Zdenek Johan, Ladislav Strnad, Vera Johan; Evolution of the Cínovec (zinnwald) Granite Cupola, Czech Republic: Composition of Feldspars and Micas, a Clue to the Origin of W, sn Mineralization. The Canadian Mineralogist 2012;; 50 (4): 1131–1148. doi: https://doi.org/10.3749/canmin.50.4.1131
  4. Ilmari Haapala, Sari Lukkari（2005）Petrological and geochemical evolution of the Kymi stock, a topaz granite cupola within the Wiborg rapakivi batholith, Finland,Lithos,Volume 80, Issues 1–4,Pages 347-362,ISSN 0024-4937,https://doi.org/10.1016/j.lithos.2004.05.012. (https://www.sciencedirect.com/science/article/pii/S002449370400297X)
  5. Harlov, D.E.; Austrheim, H. (2013). Metasomatism and the Chemical Transformation of Rock: Rock-Mineral-Fluid Interaction in Terrestrial and Extraterrestrial Environments. Berlin: Springer. doi:10.1007/978-3-642-28394-9_1. ISBN 978-3-642-28393-2.
  6. Merceron, T., Vieillard, P., Fouillac, AM. et al. Hydrothermal alterations in the Echassières granitic cupola (Massif central, france). Contr. Mineral. and Petrol. 112, 279–292 (1992). https://doi.org/10.1007/BF00310461
  7. Dudoignon, P., Beaufort, D. & Meunier, A. Hydrothermal and Supergene Alterations in the Granitic Cupola of Montebras, Creuse, France. Clays Clay Miner. 36, 505–520 (1988). https://doi.org/10.1346/CCMN.1988.0360604
  8. Lüders, V., Romer, R.L., Gilg, H.A. et al. A geochemical study of the Sweet Home Mine, Colorado Mineral Belt, USA: hydrothermal fluid evolution above a hypothesized granite cupola. Miner Deposita 44, 415 (2009). https://doi.org/10.1007/s00126-008-0221-3
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